In the top five PC companies, fourth-placed Apple registered the largest decline, with the 13 percent drop in Mac shipments. Apple's Mac sales totaled 5 million units during the quarter, declining from 5.76 million units in the same quarter a year ago.

Many Mac laptops and desktops are due for an upgrade to Intel's Skylake and Kaby Lake processors. That could grow Mac shipments. IDC's numbers do not include detachable devices like the iPad Pro.

Chromebook shipments are growing at a fast rate thanks to their use in education and could outpace Mac shipments some day. IDC expects Chromebook shipments to be sluggish in the fourth quarter, however.

The rate of decline wasn't as bad for Windows PCs makers, spurred by Windows 10 upgrades and back-to-school season shipments. HP closed in on Lenovo's spot as the world's top PC maker. Lenovo beat HP to become the world's top PC maker in 2013, but HP is looking to regain the crown.

Slower growth in China hurt Lenovo, but the company's shipments in the U.S. continued to grow. HP had shipment gains across all geographies.

Lenovo's shipments totaled 14.5 million units, declining by 3.2 percent, a 21.3 percent market share. HP's unit shipments totaled 14.4 million units, growing by 3.3 percent, a 21.2 percent market share. Shipments for third-placed Dell went up by 6.2 percent to 10.8 million units, while PC shipments for fifth-placed Asus went up 5.2 percent to 4.7 million units.